Noise introduced into touch sensor panel measurements, for example, from display data lines of a display device proximate to the touch sensor panel, can be reduced. In some examples, touch sensing operations and display operations can be synchronized. For example, touch sensing scans (or scan steps) can begin with the rising edge of a display line synchronization signal. Additionally, the display noise can be characterized for the system. Display noise characterization and timing synchronization can be used to discard touch sensing samples including display noise injected into the touch sensor panel that may be synchronized to the display data line synchronization signal. In some examples, a window can be generated based on the characterized display noise, and the window can be applied to annihilate display noise. The application of the window can be time-dependent to account for offsets between the occurrence of the display noise and the touch sensing operation.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The apparatus of claim 1, wherein applying the window function to the plurality of touch samples is time-dependent on the display timing signal associated with the display noise.
3. The apparatus of claim 1, wherein the window function comprises one or more annihilation sub-windows and wherein a periodicity of the one or more annihilation sub-windows in the window function matches a periodicity of the display noise.
6. The apparatus of claim 4, wherein the first signal transition is a first rising edge of the display timing signal and the second signal transition is a second rising edge of the display timing signal.
7. The apparatus of claim 1, wherein applying the window function to the plurality of touch samples comprises applying annihilation sub-windows to a first subset of the plurality of touch samples corresponding to a transient period of a display data line signal without applying annihilation sub-windows to a second subset of the plurality of touch samples corresponding to a settled period of the display data line signal.
9. The apparatus of claim 8, wherein applying the window function to the plurality of touch samples to remove the display noise from the plurality of touch samples occurs prior to accumulating the plurality of touch samples to determine the touch measurement.
10. The apparatus of claim 8, wherein applying the window function to the plurality of touch samples to remove the display noise from the plurality of touch samples and accumulating the plurality of touch samples to determine the touch measurement occur in one operation.
12. The method of claim 11, wherein applying the window function to the plurality of touch samples is time-dependent on the display timing signal associated with the display noise.
13. The method of claim 11, wherein the window function comprises one or more annihilation sub-windows and wherein a periodicity of the one or more annihilation sub-windows in the window function matches a periodicity of the display noise.
16. The method of claim 14, wherein the first signal transition is a first rising edge of the display timing signal and the second signal transition is a second rising edge of the display timing signal.
17. The method of claim 11, wherein the window function comprises one or more annihilation sub-windows and wherein applying the window function to the plurality of touch samples comprises applying the one or more annihilation sub-windows to a first subset of the plurality of touch samples corresponding to a transient period of a display data line signal without applying the one or more annihilation sub-windows to a second subset of the plurality of touch samples corresponding to a settled period of the display data line signal.
19. The method of claim 18, wherein applying the window function to the plurality of touch samples to remove the display noise from the plurality of touch samples occurs prior to accumulating the plurality of touch samples to determine the touch measurement.
20. The method of claim 18, wherein applying the window function to the plurality of touch samples to remove the display noise from the plurality of touch samples and accumulating the plurality of touch samples to determine the touch measurement occur in one operation.
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February 4, 2020
September 27, 2022
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